Why does soil get washed away?

Set up two trays as shown in the photo. Ask the pupils which tray they expect the soil to be washed away from more quickly. Carry out the activity - click here for a free download. Are the results as expected? What do the pupils think can be done to protect soil from erosion?
Have you tried soil painting? Click here to see some examples.
All Earthlearningidea activities can be seen on our website. We should be pleased to receive your comments about this or any of the ideas, either via this blog or by email.

What controls the speed of a tsunami wave?

Try this Earthlearningidea to find out what does control the speed of a tsunami wave In this activity, pupils look at the relationship between the depth of the water in the tank and the velocity of a water wave generated by lifting and then dropping one end of the tank.
One reader has sent us some comments and suggestions for this popular Earthlearningidea.
Try counting the number of waves which hit the end of the tank in both water depths shown in this video clip. Which is faster - shallow or deep water?
We shall be pleased to receive any suggestions for any of our Earthlearningideas.

Kitchen physics - making cross bedding

This demonstration - 'Making cross bedding' is fun.
A mixture of sand and sugar will separate into its components if poured slowly and evenly into a pile. The process can also be tried with different materials - sand, glass beads, sugar crystals - and the results are clear. Typically, larger grains will have a steeper angle of repose than smaller ones, and they will roll down the slope more energetically. The smaller grains tend to get stuck at the top of the pile, the larger ones at the base—they spontaneously segregate. But things become more complicated. As the different angles of repose of different grains are reached and exceeded, successive avalanches will be made up of different-sized grains. The cascades of smaller grains will stop first, to be then covered by a layer of the larger grains still on the move. The process repeats itself over and over, creating a layered pile. Different (and unpredictable) results can be achieved by varying the size, density, and shape of the grains and therefore their angle of stability or repose.

Imagine yourself there when the rock formed

Have you tried 'What was it like to be there - in the rocky world?' This activity brings the formation of solid rock to life. Your pupils have to imagine that they were there when the rock formed. Ask them these trigger questions -
- could you stand up?
- what would you need to survive?
- what might you see?
- what might you hear?
- what might you taste, smell?
- what might you sense?
- what might you be feeling - scared? - happy? - amazed?
We have received a reader's comments and suggestions about this activity - click here to read what she says. Do send us some of your pupils' work. They will never find rocks boring again!
We should appreciate teachers' suggestions about any of our activities. The list of activities published so far can be seen under 'Keywords' on our website.

New Earthlearningidea - Dust bowl

We have just published our latest Earthlearningidea - 'Dust bowl: investigating wind erosion'. What will happen if pupils blow through a straw, or similar tube, at a pile of dry sediment? Which of the particles is most likely to move first? What would they have to do to make all the sediment move? How far will the particles travel? Which will go furthest? How does this activity relate to the real world?
This activity could lead to an understanding of the effects of wind erosion in flat, exposed areas and dry climates. Wind erosion can have devastating effects on a region's soil, if measures are not taken to protect it.
Try this Earthlearningidea with your pupils and let us know how they get on. Please send us some photos or written descriptions of their ideas. We will publish the best in our 'Extension' ideas.

Tsunami through the window

Have you tried this activity? You only need a good imagination to do it - 'A tsunami through the window - what would you see, what would you feel?' The class is asked a series of questions about what a tsunami is like, as they look through a window or doorway (having looked at a photo or photos first). They are asked to discuss the answers in groups to provide a better 'feel' for what it might actually be like to be there. Some possible responses, for discussion, are provided in the activity.

Dangerous swelling of a volcano

This activity demonstrates how tiltmeters on volcanoes work. If the volcano 'bulges', changing shape because the magma beneath is rising, the liquid in the tiltmeter will move - sending an electric signal 'back to base'.
This an easy activity to set up and carry out. It could form part of a lesson about volcanic eruptions and their effects. Is it better to use one source or several in trying to predict an eruption? How do you prepare a response to an eruption in a volcanic area? Please let us know what your pupils think.