Background

Outreach projects about space in primary schools are important because they help shape the future of science and technology while making learning fun and engaging for young minds. This can help bridge the knowledge gap at an early age, especially for schools without the infrastructure or resources to run projects like this, as well as helping to develop critical-thinking and problem-solving skills. Outreach is designed to help inspire the next generation of future space employees, and can also be a valuable tool in helping to encourage greater diversity in STEM subjects/careers further down the line.

This activity in particular, focusing on comets, was designed to work towards these above objectives and opportunities, and is especially useful for helping with DEI-elements as it is an inclusive activity that offers a multi-sensory experience, which is beneficial for all students. The obvious precautions taken around the dry ice used in the activity also highlights to students the importance of safety in science.

The activity was developed by Jez Turner at the University of Nottingham, who is a strong proponent of championing outreach projects such as this, and was inspired by a similar activity created at the National Space Centre in Leicester.

Key Learning Points

In aiming to enthuse a younger audience into STEM, the activity asks the key questions of ‘What is a rainbow scientist and what do they do?’ By providing some historical examples of comets in popular culture(s), it aims to demonstrate that this topic is something which has been a regular presence throughout human existence. Similarly, there are learning opportunities around the chemical make-up of comets, represented (mainly) by items that can be found in a household. There is also a key learning point around safety in science, by demonstrating the seriousness taken with the dry ice.

Required Resources

• Well-ventilated classroom (or similar space)
• Presentation delivery equipment (projector or TV, laptop, etc.)
• Traditional (non-LED) light source
• Prism
• Plastic/paper cups
• Paper
• Wooden spoons
• Sandwich bags
• Sand
• Soy sauce
• Red wine vinegar
• Malt vinegar
• Salt
• Solid CO₂ (‘dry ice’)
• Water
• Nitrile gloves for students making comets
• Gloves with thermal insulation for staff handling dry ice
• Lab coats
• Eye protection

Activity Description

Section One – Presentation

The presentation provides context to the activity, introducing the topic and motivating the students for the practical element. A copy of the example slides can be found in Appendix B as well as being available as a pdf on the Making Comets Outreach Page on the Space Universities Website, and a narrated version of this is available on this page as well. Note: This narrated presentation is to provide the details that accompany the slides to enable anyone conducting the activity to deliver this themselves, and has not been recorded to be played to the students.

The presentation asks students, ‘Who wants to be a rainbow scientist?’

Slide 1 – Illustrate what you expect them to kind of get out of the activity – mainly, that they should be able to state some properties of rainbows and comets, and describe the role of engineering and how it makes discoveries. Explain that astronomers spend about 90% of their time looking at spectra and spectrum to make discoveries about objects in the night sky.

Slide 2 – With the Northern Lights, explore why we see the colours in the sky, linking between the gasses and the atmosphere and gasses glowing. Make sure that people realise that Earth is a planet in space, and that it is not separate from the universe. This means that discovering things about Earth and what happens on Earth can help us understand what is out there in the wider solar system and beyond.

Slide 3 – This is where you provide the link to rainbows; an old fashioned light source and a prism allows you to create a rainbow. Demonstrate that a rainbow is not just 7 colours, but a spectrum with no clearly defined or delineated colours. Ask the students – What do you think a rainbow is? Allow them to discuss this, without giving any right or wrong answers, and encourage them to come up with some reasonable ideas to explore rainbows. This is also a good opportunity to ask if they would like to be a rainbow scientist.

Slide 4 – This slide helps to connect rainbows with the colour of the of the stars in Kemble’s Cascade, which demonstrates both the chemicals that the star is made of as well as the temperature of the star itself. Get the students to think about a rainbow and think about atoms, how atoms can produce light, and how atoms can absorb light. Using a spectrometer, tiny dark lines can be seen where light has been absorbed, showing the presence of elements like calcium and iron and magnesium.

Slide 5 – This is a demonstration of another activity, called a ‘Whoosh Bottle’, which helps to demonstrate how different chemicals burn in different colours.

Slide 6 – This slide shows chondrite that has been put underneath a microscope for some chemical analysis based on the light and reflection of the light.

Slide 7 – This slide shows an excerpt of the Bayeux Tapestry, depicting the Battle of Hastings. In the Tapestry, there are people who can be seen pointing at a hairy star, which was a foreboding portend and seen as a ‘harbinger of doom.’

Slide 8 – By working backwards, we have been able to work out that this ‘hairy star’ was actually Haley’s Comet, which appears every 76 years.

Slide 9 – These are images of Comet Halley in 1910 and 1986. This is an opportunity to ask the students to think about what a comet is, explaining that there isn’t a definitive definition because some asteroids have comet-like properties and some comets have asteroid-like properties. Explain that these comets are coming from way out in the solar system and as they get close to the sun, they start to sublimate, and their dust gets blown away by the solar wind, creating tails. Looking at the light from this, we can analyse this light and find out what they’re made of by using rainbow science.

Slide 10 – Ask the students to think about smelling a comet, because when Rosetta and Philae landed on the surface and did some chemical sniffing, they confirmed some of these observation from spectroscopy, about the chemical makeup of these comets.

Slide 11 – This accompanies that practical element of the activity, and is left visible throughout Section Two.

Section Two – Practical

Following the main section of the presentation, the practical element can then begin. A video demonstration of the activity can be found on the Making Comets Outreach Page on the Space Universities Website.

The activity can be carried out by individual students through to groups of up to 6, depending on the space/materials available. All students must be wearing their PPE from this point. Put paper down first before starting the comet making experiment.

Step 1 – Have the students line their plastic cups with a food bag.

Step 2 – The students can now add several spoons of sand to the cup; this does not have to be an exact amount or even between participants, reflecting the fact that comets come in different shapes and sizes.

Step 3 – They now begin to add further materials, giving a good stir between each one. These are the red wine vinegar (representing alcohol), the malt vinegar (representing acid), the soy sauce (representing organic matter), and the salt. These can be added in any order, and can again be added in varying amounts.

Step 4 – Students add water, approximately one third of the volume of the cup. Be sure they do not add too much water to ensure the dry ice has the desired effect in a good time. Stir the mixture again.

Step 5 – This step requires the staff member responsible for the dry ice to upgrade their PPE to include the thermal gloves. As you go around to add the dry ice, make sure to emphasise to the students that they should not touch their comets with the dry ice inside, and should not touch the dry ice directly.

Step 6 – Add 2-3 scoops of dry ice to each cup, and then give the cup a shake. Explain that the dry ice will be freezing the water in their cup.

Step 7 – At this stage, tell the students that the dry ice is freezing the comet, simulating the effects of deep space; the room is acting like the Sun as the heat source affecting the comet. As the room heats the dry ice, it is the same as the comet getting closer to the Sun, increasing in temperature, and the liquids and gasses are undergoing change, which is why their comets will be making hissing or popping noises.

Step 8 – Encourage the students to make observations about their comets – what does it look like, smell like, or sound like? Make sure they still do not touch the comets at this stage.

Step 9 – When the comet has sufficiently warmed up, the students will be able to draw the mixture together in the food bag and squeeze it in their gloved hands, allowing them to feel the comet binding into a solid mass.

Step 10 – Pour any liquid back into the cup and then carefully pull the edges of the bag back to expose the freshly made comets.

Step 11 – Ensure everything is tidied up thoroughly after the activity, checking for any dry ice that may have been spilled, and making sure that the dry ice container is secured.

Section Three – Presentation

Slide 12 – As a further activity/homework, encourage the students to watch ESA’s video on Rosetta and Philae (this is approximately 25 minutes in length): https://www.youtube.com/watch?v=HD2zrF3I_II

Slide 13 – Return to and reinforce the objectives of the activity. Ask the students to reflect on what they have learnt and who they could discuss this with. Ask for one thing they are going to take away and share with someone who wasn’t in the room for the activity, such as a friend or family member. Remind them that they could become a rainbow scientist.

General Information

Chemicals Used:

Sand

Water

Soy sauce

Vinegars

Solid CO₂ (dry ice)

 

Special precautions for chemicals and experimental work:

Solid CO₂ needs a vent, for expansion.

Eyes must be protected; no exposed skin; thermal protection gloves must be used to limit the very low risk of solid CO₂ coming in contact with skin or eyes. This will also prevent sand or soy source getting in the eyes.

Adequate ventilation is needed to limit the very low risk of asphyxiation from CO₂ inhalation.

 

Physical conditions:

Temperature: −78.5°C

Pressure: Atmospheric

 

Environmental considerations:

Do not empty into drains.

 

Details of any biological effects:

No biohazards.

Risk Assessment

The following three hazards are applicable to all persons in the vicinity of the activity, including staff delivering the outreach, school staff, students, and any other persons involved or in the room in which the activity is taking place.

 

Hazard 1: Adequate ventilation is needed to limit the very low risk of asphyxiation from CO₂ inhalation.

Associated Risk: 10 kg of dry ice will produce 5 m³ of gas, raising the level of CO₂ from 0.035% (natural) to safe-limit of 0.5% in a room 3m high by 19m on a side.

Risk Control Measures: Adequate ventilation is needed to limit the very low risk of asphyxiation from CO₂ inhalation. Windows should be open. Any room must be checked to ensure adequate ventilation before experiment is carried out (assuming that full opening of doors/windows will not in any other way cause a hazard to students).

 

Hazard 2: Cold ‘burns’ from solid CO₂.

Associated Risk: Dry ice sublimes at -78°C and will cause serious skin ‘burns’ on contact, but momentary contact is unlikely to be a problem.

Risk Control Measures: Only trained staff should use the solid CO₂, with all other people standing at least 1m away. Eyes must be protected with goggles/safety glasses, there must be no exposed skin, and thermal protection gloves must be used, to limit the low risk of solid CO₂ coming in contact with skin or eyes. This will also prevent sand or soy source getting in the eyes. Schools must be told in advance to make sure that students have long sleeves and covered legs. No open shoes, to prevent ‘burns’ to feet.

In the event of any cold ‘burns’, follow the processes listed below in the ‘Emergency Procedures’ section.

 

Hazard 3: Solid CO₂ needs a vent for expansion or it will pressurise any container.

Associated Risk: Explosion of container.

Risk Control Measures: Nitrogen-rated sealed container with a vent hole for expansion should be used for transport.

 

Please note – this risk assessment should not be considered exhaustive. Please ensure that you have conducted a full risk assessment before conducting this activity.

Emergency Procedures

Spillage/Accidental Release

Ventilate area by opening windows/doors and make sure people exit the room via a route away from the solid CO₂ (routes must be considered when planning the experiment) while a standard dustpan and brush are used to put it back in storage container.

 

Fire-Fighting Measures:

No specific recommendations; material will not burn. In case of fire in the surroundings, use appropriate extinguishing agent.

 

First Aid Measures:

Eye Contact

Apply copious amounts of tepid water to the affected area of skin to reduce freezing in the tissue, loosen any clothing that may restrict blood circulation, and move the injured person to a warm place but not a hot environment. Do not apply heat to any affected parts. In case of frostbite, spray with water for at least 15 minutes. To protect frozen areas, apply a loose, non-fluffy sterile dressing. Seek medical attention immediately.

Skin Contact

Apply copious amounts of tepid water to the affected area of skin to reduce freezing in the tissue, loosen any clothing that may restrict blood circulation, and move the injured person to a warm place but not a hot environment. Do not apply heat to any affected parts. In case of frostbite, spray with water for at least 15 minutes. To protect frozen areas, apply a loose, non-fluffy sterile dressing. Seek medical attention immediately.

Ingestion

Swallowing must be absolutely avoided, since coldness and developing pressure could be dangerous. Obtain immediate medical attention and take along these instructions.

Inhalation

Low concentrations of CO₂ cause increased respiration and headache. In high concentrations, this may cause asphyxiation. Symptoms may include loss of mobility/consciousness. Victim may not be aware of asphyxiation. Remove victim to uncontaminated area wearing self-contained breathing apparatus. Keep victim warm and rested. Call for emergency medical support. Apply artificial respiration if breathing stopped.

Presentation Slides